Ancient pool of warm water questions current climate models

Date:

April 3, 2013

Source:

University College London

Summary:

A huge pool of warm water that stretched out from Indonesia over to Africa and South America four million years ago suggests climate models might be too conservative in forecasting tropical changes. Present in the Pliocene era, this giant mass of water would have dramatically altered rainfall in the tropics, possibly even removing the monsoon. Its decay and the consequential drying of East Africa may have been a factor in Hominid evolution. The missing data for this phenomenon could have significant implications when predicting the future climate.

Share:

Total shares:

FULL STORY

Ocean. When analysing all the available sea surface temperature records spanning the past five million years, scientists found that none of the currently proposed mechanisms can account for such conditions in the Pliocene, when tested using a climate model.

Credit: Copyright Michele Hogan

Ocean. When analysing all the available sea surface temperature records spanning the past five million years, scientists found that none of the currently proposed mechanisms can account for such conditions in the Pliocene, when tested using a climate model.

Credit: Copyright Michele Hogan

A huge pool of warm water that stretched out from Indonesia over to Africa and South America four million years ago suggests climate models might be too conservative in forecasting tropical changes.

Present in the Pliocene era, this giant mass of water would have dramatically altered rainfall in the tropics, possibly even removing the monsoon. Its decay and the consequential drying of East Africa may have been a factor in Hominid evolution.

Published in Nature today, the missing data for this phenomenon could have significant implications when predicting the future climate.

When analysing all the available sea surface temperature records spanning the past five million years, the international team -- with academics from UCL and Yale -- found that none of the currently proposed mechanisms can account for such conditions in the Pliocene, when tested using a climate model.

"Essentially, we've looked at a warm world in the past and it shows changes in the pattern of tropical sea surface temperatures. We've analysed all the existing theories to explain this vast pool of ancient warm water, and even in combination they can't explain something as odd as this," said Dr Chris Brierley (UCL Geography), a co-author of the paper.

Occurring between three and five million years ago, the Pliocene was the last time the world was in a steady climate that was warmer, and with a carbon dioxide level higher than the conditions that existed before the Industrial Revolution. As a result, it has attracted strong attention as a possible basis for future climate conditions once carbon dioxide levels have been stabilized.

The three critical conditions that defined the tropical Pliocene climate were:

Evidence of the maximum ocean temperature not being much warmer;

Reduced east-west temperate differences; and

Weaker north-south differences in the tropics.

It is these three conditions that the team say that any future efforts at modelling the past must explain.

"An important question is how much the evidence of climate evolution over the last five million years shapes our assessment of future change. From these observations, it is clear that the climate system is capable of remarkable transformations even with small changes in external parameters such as carbon dioxide," said Dr Brierley.

"Therefore, explaining the discrepancy between model simulations and the early Pliocene temperature patterns is essential for building confidence in our climate projections.

"In many ways, this work on past climates is part of understanding the uncertainty of future climate. It can give us a heads-up of potential climates that we hadn't imagined possible before." added Dr Brierley.

University College London. "Ancient pool of warm water questions current climate models." ScienceDaily. ScienceDaily, 3 April 2013. <www.sciencedaily.com/releases/2013/04/130403131352.htm>.

University College London. (2013, April 3). Ancient pool of warm water questions current climate models. ScienceDaily. Retrieved August 2, 2015 from www.sciencedaily.com/releases/2013/04/130403131352.htm

University College London. "Ancient pool of warm water questions current climate models." ScienceDaily. www.sciencedaily.com/releases/2013/04/130403131352.htm (accessed August 2, 2015).

July 31, 2015  Resettlement projects in the Amazon are driving severe tropical deforestation, according to new research. Widely hailed as a socially responsible and 'innocuous' strategy of land redistribution, ... read more

July 31, 2015  The humble butterfly could hold the key to unlocking new techniques to make solar energy cheaper and more efficient, pioneering new research has shown. By mimicking the v-shaped posture adopted by ... read more

July 30, 2015  China needs to reduce its dependence on coal and improve the range of fuels it uses if it is to have long term energy security, according to new research. The study looks at the future of electricity ... read more

July 30, 2015  North of the Aleutian Islands, submarine canyons in the cold waters of the eastern Bering Sea contain a highly productive 'green belt' that is home to deep-water corals as ... read more

July 30, 2015  New findings have implications for questions regarding how animals and plants grow minerals into shapes that have no relation to their original crystal symmetry, and why some ... read more

July 30, 2015  A new study addresses an important question in climate science: how accurate are climate model projections? Climate models are used to estimate future global warming, and their accuracy can be ... read more

Apr. 3, 2013  Climate models for the early Pliocene might be missing key processes. If researchers can uncover these missing processes, they can apply them to models of modern climate and improve future climate ... read more

May 19, 2013  How will rainfall patterns across the tropical Indian and Pacific regions change in a future warming world? Climate models generally suggest that the tropics as a whole will get wetter, but the ... read more

Jan. 23, 2013  The amount of rainfall and number of tropical storms during a summer monsoon season greatly impact the agriculture, economy, and people in Asia. A promising breakthrough for predicting in spring the ... read more